Add custom date range support to profit analytics

Introduces a date range picker to the profit analytics dashboard, allowing users to select custom date ranges for profit calculations. Updates ProfitAnalyticsChart and profit-analytics-service to handle both period and date range queries, improving flexibility and user experience.

lib/services/profit-analytics-service.ts

@@ -2,6 +2,8 @@ import { apiRequest } from '../api';
 
 export interface ProfitOverview {
   period: string;
+  startDate?: string;
+  endDate?: string;
   summary: {
     totalRevenue: number;
     revenueFromTrackedProducts: number;
@@ -40,10 +42,45 @@ export interface ProfitTrend {
   profitMargin: number;
 }
 
-export const getProfitOverview = async (period: string = '30'): Promise<ProfitOverview> => {
-  return apiRequest(`/analytics/profit-overview?period=${period}`);
+export interface DateRange {
+  from: Date;
+  to: Date;
+}
+
+export const getProfitOverview = async (
+  periodOrRange?: string | DateRange
+): Promise<ProfitOverview> => {
+  let url = '/analytics/profit-overview';
+  
+  if (periodOrRange && typeof periodOrRange !== 'string') {
+    // Date range provided
+    const startDate = periodOrRange.from.toISOString().split('T')[0];
+    const endDate = periodOrRange.to.toISOString().split('T')[0];
+    url += `?startDate=${startDate}&endDate=${endDate}`;
+  } else {
+    // Period provided (backward compatibility)
+    const period = periodOrRange || '30';
+    url += `?period=${period}`;
+  }
+  
+  return apiRequest(url);
 };
 
-export const getProfitTrends = async (period: string = '30'): Promise<ProfitTrend[]> => {
-  return apiRequest(`/analytics/profit-trends?period=${period}`);
+export const getProfitTrends = async (
+  periodOrRange?: string | DateRange
+): Promise<ProfitTrend[]> => {
+  let url = '/analytics/profit-trends';
+  
+  if (periodOrRange && typeof periodOrRange !== 'string') {
+    // Date range provided
+    const startDate = periodOrRange.from.toISOString().split('T')[0];
+    const endDate = periodOrRange.to.toISOString().split('T')[0];
+    url += `?startDate=${startDate}&endDate=${endDate}`;
+  } else {
+    // Period provided (backward compatibility)
+    const period = periodOrRange || '30';
+    url += `?period=${period}`;
+  }
+  
+  return apiRequest(url);
 };